Oscillator using a pencil triode



Feb. 17, 1959 D. L. JAFFE OSCILLATOR USING A PENCIL TRIODE Filed Nov. 8. 1954 IN V EN TOR. Q M/m /vef flf/f BY @MWEW United States Patent Ofifice 2,874,288 Patented Feb. 17, 1959 OSCILLATOR USING A PENCIL TRIODE David Lawrence Jatfe, Great Neck, N. Y., assignor to Polarad Electronics Corporation, Brooklyn, N. Y., a corporation of New York Application November 8, 1954, Serial No. 467,344

14 Claims. (Cl. 25036) The present invention relates to oscillators and especially to an oscillator tunable over a wide range frequency centered at a wave length near 10 centimeters.

More particularly still the invention relates to a unitary oscillator utilizing an electron tube of the pencil triode type such as is commercially available and designated, for example, as RCA type 5893.

The structure of the invention provides an oscillator wherein the electron tube is housed within certain tunable elements thereby providing a small, compact, complete oscillator.

It is an object of the invention to provide a broad band high frequency oscillator which is extremely compact and which utilizes an electron tube of the pencil triode type.

It is another object of the invention to provide such an oscillator which is readily tunable to the desired frequency within a band of frequencies.

It is another object of the invention to provide an oscillator of the type described wherein the electron tube is housed within the tunable elements and is directly connected to these elements without the necessity of long conductors interconnecting parts.

Other objects and features of the invention will be apparent when the following description is considered in connection with the annexed drawings, in which,

Figure 1 is an end View of the oscillator of my invention;

Figure 2 is a cross-sectional view of the oscillator, the view being taken on the plane of the line 22 of Figure 1;

Figure 3 is a transverse cross-sectional view taken on the plane of the line 3-3 of Figure 2;

Figure 4 is a fragmentary transverse cross-sectional view taken on the plane of the line 4-4 of Figure 2; and

Figure 5 is a similar fragmentary transverse crosssectional view taken on the plane of the line 55 of Figure 2.

Referring now to the drawings and particularly to Figure 2, there is shown at a pencil triode electron tube having the usual cylindrical anode 11 and the usual grid flange 12 together with the cathode sleeve 13. The triode 10 is mounted within a cylindrical tube 14 which tube cooperates with other parts hereinafter mentioned to form two resonant cavities, one of which is at the left hand end of the structure and constitutes the anode cavity and the other of which is at the right hand end of the structure and constitutes the cathode cavity.

Fixed to the cylinder 14 at its right hand end is a disk 15 having an inwardly projecting sleeve 16 secured thereto. Centrally of the disk 15 there is mounted therein a sleeve 17 which, when the structure is assembled as shown in the drawings, bears against the cathode sleeve 13 of the triode 10 and constitutes a connection thereto. The sleeve 17 has mounted thereon a cup-shaped member 18 which extends toward the right and cooperates with the sleeve 16 to form a folded line arrangement, the sleeve 17 and this folded line arrangement cooperating with the right hand end portion of the cylinder 14, that is, the portion lying to the right of the grid flange 12, to form the cathode line or cathode resonant cavity. The folded line arrangement mentioned serves to reduce the overall length of the cathode line while securing the proper operating frequency.

In order to adjust the resonance points of the cathode line there is provided a plate 20 fixed to the cup member 18 and extending to the left thereof as shown in Figures 2 and 3. Radially outward of the plate 20 and variably spaced therefrom i a plate 21 which plate is supported on a spring leaf 22 inserted in an aperture in the disk 15. A screw 23 is threaded through the wall of cylinder 14 and extends through a clearance opening in the spring 22 and bears against the plate 21. Thus the capacity between plates 20 and 21 may be adjusted to vary the capacitance across the transmission line or resonant cavity and adjust the tuning of this line. A screw 24, which is threaded in the wall of the tube 14 adjacent screw 23, serves to limit the movement of spring 22.

Mounted on the grid flange 12 of the pencil triode 10 is a disk 25 having a flange or sleeve 26 extending to the left thereof, the disk 25 having a second flange 27 extending to the right and cooperating with clamping rings 28 and 29 to hold the disk 25 rigidly on the flange 12. Mounted in the flange or sleeve 26 at spaced points circumferentially thereof are the insulating buttons 31 which buttons serve to space the disk 25 and sleeve 26 in the tube 14 and likewise of course serve to position the pencil triode 10 centrally of the tube 14. The length and diameter of the sleeve 26 are chosen to provide a proper amount of feedback between the plate and cathode lines in order to produce sustained oscillations at maximum power level. The sleeve 26 has a diameter close to that of tube 14 to form a low-impedance coaxial line section therewith, so that the cathode and anode cavities are loosely coupled and can be independently tuned.

A leaf spring 32 extends along the inner wall of the tube 14 at the upper portion thereof, this spring making contact with the sleeve 26 at one edge and being fixed at its opposite edge to one element of a button condenser 33. A D. C. connection to the triode grid electrode is thus made through the condenser 33, leaf spring 32, sleeve 26 and disk 25. The button condenser, in addition to functioning as part of the D. C. connection to the triode grid, serves also as a radio-frequency bypass condenser.

Mounted upon the anode 11 of tube 10 is a thrust washer 34 and a sleeve 35 which sleeve serves as the inner conductor of the anode line. This sleeve is threaded at its right hand end as indicated at 36. Rotatably mounted upon the sleeve 35 adjacent its left hand end is a bevelled gear 37 having a splined cylindrical extension 38 fixed thereto. Cooperating with the extension 38 is a cup-shaped member 40 having fingers 41 extending to the left thereof. Member 40 has a central bore therein which is threaded to mate with the thread 36 on sleeve 35. Consequently as the gear 37 is rotated member 40 moves longitudinally of the tube 14 thus causing the frequency of oscillation to vary by adjusting the effective length of the anode line, the member 40 acting as a tuning slug.

A bevel gear 42 is mounted upon a screw 43 which is in turn rotatably mounted in a bushing 44 fixed in the wall of tube 14. Thus by inserting a screw driver in the slotted head of screw 43 the gear 42 may be rotated in either direction causing the cup-shaped member or turning slug 40 to move axially and adjust the frequency.

Mounted upon the sleeve 35 near the left end thereof are the axially extending cylindrical members 45 and 46 which members overlap in the axial direction forming a folded line arrangement for the plate line similar to the structure already described for the cathode line. This folded line arrangement serves to reduce the overall length of the anode or plate line necessary to provide the proper operating frequency.

The various elements thus far described are held in their proper position within the tube 14 by means of a plug 47 which threads into the open left hand end of the tube 14 and presses the anode sleeve 35 against the thrust washer 34 in turn pressing the pencil triode toward the right as shown in Figure 2 with the cathode flange thereof against a thrust washer which in turn bears against the left hand end of the cathode sleeve 17. A screw 48 extends through a second plug member 50 and threads into the left end of the anode sleeve 35. Member 50 is insulated from sleeve 35 and screw 48 by insulators 55. Mounted under the head of this screw is a terminal 51 to which the lead from the plate'supply is flxed.

The radio frequency output is taken off through a radio frequency connector 52 which is connected to the inner conductor 17 of the cathode line by means of a coaxial line 53, the tap off point on the cathode line being so chosen as to provide an impedance match to the output line.

Connection to the filament of the pencil triode 10 is made through a socket 54 which slides into the right hand end of the cathode sleeve 17 and engages the usual prongs 55 of the triode 10, the socket 54 being held in place by means of the resilient clip 56 which extends through slots 57 in the cathode sleeve 17 and the ends of which lie in a groove 58 in the socket 54.

It will be seen that the structure described above forms a compact self-contained oscillator having a pencil triode mounted in the interior of a protective metallic tube which tube, in addition to protecting the electron tube, also serves as the outer conductor of two resonant cavities or transmission lines, one of which serves as an anode cavity and the other as a cathode cavity. Furthermore, the frequency of operation may .be readily adjusted by the turning of a single screw which adjusts the tuning slug in the plate cavity.

An additional tuning adjustment may be effected by means of the condenser which is mounted within and is circuit-wise included in the grid cathode line; In grid pulse operation positive pulses are supplied to the grid electrode through the grid flange 12 and the condenser 31 above described. In continuous wave and plate pulse operation the grid connection is tied to the cathode.

Due to the construction described the outer tube 14 of the entire cavity operates at cathode potential, thereby eliminating shock hazards and making the oscillator more readily mounted without the necessity of utilizing insulative mounting brackets or the like.

While I have described a preferred embodiment of my invention, it will be understood that I wish to be limited not by the foregoing description, but solely by the claims granted to me.

What is claimed is:

1. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cylindrical cathode terminal and a grid flange therebetween, in combination, a cylindrical metallic housing, said housing having an internal diameter substantially that of the grid flange of the triode, said flange dividing said cylindrical housing into two sections, a sleeve surrounding the cylindrical cathode and electrically connected thereto, a disk closing the adjacent end of said housing and connected to said sleeve, said sleeve comprising with the section of said housing on one side ofv said flange an adjustably resonant transmission line section, a threaded sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said sleeve forming a second resonant transmission line section with said other section of said housing, and means independently to adjust said transmission line sections to select a desired operating frequency for the oscillator, the means to adjust said second transmission line comprising a tuning slug threadedly mounted on said threaded sleeve, and means whereby said slug may be rotated from the exterior of the housing to adjust the tuning of said anode line.

2. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cylindrical cathode terminal and a grid flange therebetween, in combination, a cylindrical metallic housing, said housing having an internal diameter substantially that of the grid flange of the triode, said flange dividing said cylindrical housing into two sections, a sleeve surrounding the cylindrical cathode and electrically connected thereto, a disk closing the adjacent end of said housing and connected to said sleeve, said sleeve comprising with the section of said housing on one side of said flange an adjustably resonant transmission line section, a sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said sleeve forming with said other section of said housing, a second resonant transmission line section, means independently to adjust said transmission line sections to select a desired operating frequency for the oscillator, and means for supporting the triode centrally of said housing, said supporting means comprising means fixing said cathode sleeve in said cathode closure disk centrally thereof, said supporting means likewise comprising an axially extending cylinder fixed to the grid flange of the triode, said cylinder having insulating buttons spaced about its periphery thereby spacing the triode equally from the interior Walls of said housing and locating the triode centrally within said housing.

3. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cylindrical cathode terminal and a grid flange therebetween, in combination, a cylindrical metallic housing, said housing having an internal diameter substantially that of the grid flange of the triode, said flange dividing said cylindrical housing into two sections, a sleeve surrounding the cylindrical cathode and electrically connected thereto, a disk closing the adjacent end of said housing and connected to said sleeve, said sleeve comprising with the section of said housing on one side of said flange an adjustably resonant transmission line section, a sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said sleeve forming with said other section of said housing, a second resonant transmission line section and means independently to adjust said transmission line sections to select a desired operating frequency for the oscillator, said cathode sleeve and the cylindrical cathode of the triode extending outwardly through said cathode closure disk, said extended portion of said sleeve forming a housing for a socket insertable over prongs of the triode forming a filament connection thereto, said sleeve extension having an annular groove therein mating with a similar groove in said socket and a spring clip inserted through the groove in said sleeve extension into the groove in said socket to hold said socket in position.

4. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cylindrical cathode terminal and a grid flange therebetween, in combination, a cylindrical metallic housing, said housing having an internal diameter substantially that of the grid flange of the triode, said flange dividing said cylindrical housing into two sections, a sleeve surrounding the cylindrical cathode and electrically connected thereto, a disk closing the adjacent end of said housing and connected to said sleeve, said sleeve comprising with the section of said housing on one side of said flange an adjustably resonant transmission line section, a sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said sleeve forming with said other section of said housing a second resonant transmission line section, means independently to adjust said resonant transmission line sections to select a desired operating frequency for the oscillator, a cup-shaped member fixed to said cathode sleeve, a further sleeve extending from said closure disk and having a diameter different from that of said cupshaped member and axially overlapping said cup-shaped member, said cup-shaped member and said further sleeve comprising with said cathode sleeve a folded line arrangement effectively modifying the length of said cathode transmission line section, said cup-shaped member having a plate extending therefrom in an axial direction, said plate being electrically connected to said member, and a second plate mounted radially outwardly of said firstmentioned plate, said two plates together forming a condenser, said second plate being adjustable to vary the capacity of said condenser and to adjust the resonant frequency of said cathode line.

5. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cylindrical cathode terminal and a grid flange therebetween, in combination, a cylindrical metallic housing, said housing having an internal diameter substantially that of the grid flange of the triode, said flange dividing said cylindrical housing into two sections, a sleeve surrounding the cylindrical cathode and electrically connected thereto, a disk closing the adjacent end of said housing and connected to said sleeve, said sleeve comprising with the section of said housing on one side of said flange an adjustably resonant transmission line section, a sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said sleeve forming with said other section of said housing a second resonant transmission line section, means independently to adjust said resonant transmission line sections to select a desired operating frequency for the oscillator, a disk closing said housing at the anode end thereof, a cup-shaped member mounted on said anode sleeve, a flange mounted on said anode closure disk, said flange and cup member being axially overlapping to comprise a folded line arrangement to effectively modify the length of said anode transmission line, said anode closure disk being threadedly mounted in said housing and further characterized in that said disk bears against said anode sleeve and presses the triode into position with a flange thereon resting against said fixed cathode sleeve to thereby hold the triode in position.

6. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cylindrical cathode terminal and a grid flange therebetween, in combination, a cylindrical metallic housing, said housing having an internal diameter substantially that of the grid flange of the triode, said flange dividing said cylindrical housing into two sections, a sleeve surrounding the cylindrical cathode and electrically connected thereto, a disk closing the adjacent end of said housing and connected to said sleeve, said sleeve comprising with the section of said housing on one side of said flange an adjustably resonant transmission line section, a sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said sleeve forming with said other section of said housing a second resonant transmission line section, means independently to adjust said resonant transmission line sections to select a desired operating frequency for the oscillator, said anode sleeve being threaded, a tuning slug threadedly mounted on said threaded sleeve, and means for rotating said sleeve from the exterior of the housing to adjust the tuning of said anode line section, said tuning slug being cup-shaped, the marginal portion thereof being provided with notches, and said rotating means comprising a bevel gear rotatably mounted on said anode sleeve, said gear carrying a flange having splines thereon, said splines engaging said notches of said tuning slug to rotate said slug as said gear is rotated to thereby move said slug axially along said anode sleeve, and a second bevel gear mating with said first bevel gear and rotatably supported in the wall of said housing.

7. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cylindrical cathode terminal and a grid flange therebetween, in combination,

a cylindrical metallic housing, said housing having an internal diameter substantially that of the grid flange of the triode, said flange dividing said cylindrical housing into two sections, a sleeve surrounding the cylindrical cathode and electrically connected thereto, a disk closing the adjacent end of said housing and connected to said sleeve, said sleeve comprising with the section of said housing on one side of said flange an adjustably resonant transmission line section, a sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said sleeve forming with said other section of said housing a second resonant transmission line section, means independently to adjust said resonant transmission line sections to select a desired operating frequency for the oscillator, and means for supporting the triode centrally of said housing, said supporting means comprising means fixing said cathode sleeve in said cathode closure disk centrally thereof, said supporting means likewise comprising an axially extending cylinder fixed to the grid flange of the triode, said cylinder having insulating buttons spaced about its periphery thereby spacing the triode equally from the interior walls of said housing and locating the triode centrally within said housing, said flange serving as an electrical connection to the grid of the triode, said electrical connection comprising a condenser insulatingly mounted in the wall of said housing and an electrically conducting resilient finger mounted on said condenser within said housing, said finger bearing against said rim of said grid flange.

8. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cylindrical cathode terminal and a grid flange therebetween, in combination, a cylindrical metallic housing, said housing having an internal diameter substantially that of the grid flange of the triode, said flange dividing said cylindrical housing into two sections, a sleeve surrounding the cylindrical cathode and electrically connected thereto, a disk closing the adjacent end of said housing and connected to said sleeve, said sleeve comprising with the section of said housing on one side of said flange an adjustably resonant transmission line section, a sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said sleeve forming with said other section of said housing a second resonant transmission line section, and means independently to adjust said resonant transmission line sections to select a desired operating frequency for the oscillator, said cathode sleeve and the cylindrical cathode of the triode extending outwardly through said cathode closure disk, said extended portion of said cathode sleeve forming a housing for a socket insertable over prongs of the triode forming a filament connection thereto, said cathode sleeve extended portion having an annular groove therein mating with a similar groove in said socket, and a spring clip inserted through the groove in said sleeve extended portion into the groove in said socket to hold said socket in position, and an axial extension of said grid flange of a length to provide a desired coupling between the input and output circuits of said oscillator.

9. A device as claimed in claim 5, characterized in that said anode closure disk is provided with a central opening therein and said anode sleeve is provided with a threaded opening therein centrally thereof and adjacent said anode closure disk and a screw inserted through said disk and mounted in said anode sleeve and serving as a terminal for a plate voltage supply.

10. A device as claimed in claim 6, characterized in that said second bevel gear is fixedly mounted on a screw in turn rotatably mounted in said housing, said screw having a slotted head to facilitate the adjustment of said tuning slug.

11. In a high frequency oscillator utlizing a triode having a cylindrical anode terminal, a cylindrical cathode terminal and a grid flange therebetween, in combination, a cylindrical metallic housing, said housing having an internal diameter substantially that of the grid flange of the triode, said flange dividing said cylindrical housing into two sections, a sleeve surrounding the cylindrical cathode and electrically connected thereto, a closure for the adjacent end of said housing and connected to said sleeve, said cathode sleeve forming part of a resonant transmission line section, with the section of said housing on one side of said flange, a sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said sleeve forming a part of a second resonant transmission line section with said other section of said housing and a further sleeve adapted to be secured to said grid flange and extending axially in closely spaced insulated relation within said housing to provide a desired coupling between said transmission line sections.

12. A device as in claim 11 further including a plurality of insulating elements between said further sleeve and said housing and spacing said further sleeve from said housing, whereby said triode is centered and retained in said housing.

13. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cathode terminal and a grid flange therebetween, in combination, a cylindrical metallic housing, said housing being coupledto the grid flange of the triode, a threaded sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said anode forming a resonant transmission line section with a portion of said housing, and means for adjusting said transmission line section comprising a tuning slug threadedly mounted on said threaded sleeve, and means whereby said slug maybe rotated from the exterior of the housing to adjust the tuning of said anode line.

14. In a high frequency oscillator utilizing a triode having a cylindrical anode terminal, a cathode terminal and a gridflange therebetween, in combination, a cylindrical metallic housing, said housing being coupled to the grid flange of the triode, a threaded sleeve surrounding the anode of said triode and electrically connected to said anode, a closure for said housing at the end of said anode sleeve, said anode forming a resonant transmission line section with a portion of said housing, and means for adjusting said transmission line section comprising a tuning slug threadedly mounted on said threaded sleeve, and means whereby said slug may be rotated from the exterior of the housing to adjust the tuning of said anode line, said tuning slug. being cup-shaped, the marginal portion thereof being provided with notches, and said rotating means comprising a bevel gear rotatably mounted on said anode sleeve, said gear carrying a flange having splines thereon, said splines engaging said notches of said tuning slug to rotate said slug as said gear is rotated to thereby move said slug axially along said anode sleeve, and a second bevel gear mating with said first bevel gear and rotatably supported in the wall of said housing.

References Cited in the file of this patent UNITED STATES PATENTS 2,408,355 Turner Sept. 24, 1946 2,428,622 Gurewitsch Oct. 7, 1947 2,429,760 Hotine Oct. 28, 1947 2,465,801 Gurewitsch Mar. 29, 1949 2,617,038 Russell Nov. 4, 1952 2,750,504 Sontheimer et al. June 12, 1956 

